The energy requirements and attendant costs are relatively high when pumping heavy crudes. The problem is very severe when water invades the wellbore and forms an emulsion with the produced crude. In some cases, the restrictions to flow due to the viscous emulsion in the wellbore is greater than the flow capacity of the formation to the wellbore, and thus, the production rate is drastically lowered. A typical curve showing the increase in viscosity with increase in percentage of water is illustrated in FIG. 1. One method disclosed in U.S. Pat. No. 3,670,752 comprises dissolution of gas in the crude oils and tars at sub-freezing temperatures for pipeline transporting. The cost of freezing all of the crude is prohibitive. Other attempts to reduce the viscosity of the produced oil, as in Pat. Nos. 3,380,531; 3,425,429; and 3,467,195 were to add water and a base, such as sodium hydroxide in the presence of an emulsifying agent to provide an oil-in-water emulsion with various concentrations, such as of 30-50 percent water and 70-50 percent oil. Numerous surfactants are disclosed as emulsifiers as disclosed in 3,491,835 and 3,519,006. This addition of large amounts of expensive chemicals is prohibitive in cost, practicality, and safety.